My 1974 Plymouth Duster 360 4-speed.
It does not have a V12 code, but has 'J54 - Performance hood treatment' code instead.
Comparing to GOLDMYN's earlier post, it appears that the V21 code ended in model year 1973 on the Duster.










1969 Dodge Super Bee A12 (440 Six Pack, 4-speed, Dana 60 4.10)

1972 Plymouth Road Runner (400, 4-speed, 8.75" 3.23)

1974 Plymouth Duster 360 (360, 4-speed, 8.75" 3.23)